1. Field of the Invention
The present invention relates to a temperature and/or pressure resistant hose, in particular, a hose for vehicle engine cooling liquid circuits.
2. Background Information
Italian Utility Patent n. 219.178, filed on 20 Dec. 1989, relates to a flexible two-wall conduit comprising smooth rigid portions, and flexible corrugated portions for adapting it to the required assembly configuration, and which is lightweight, cheap to produce, and compact to store and transport. Moreover, the double wall, formed of two layers of different materials, provides for good resistance to external agents, temperature, and the liquid inside the conduit.
The above known conduit, however, is susceptible to improvement as regards stretch resistance under high temperature and/or pressure conditions. In fact, when subjected to high temperature and/or pressure, the hose, featuring bellows portions, stretches and may even yield permanently, which is not only undesirable but also forbidden by current standards in some countries, when the amount of stretch exceeds a predetermined percentage.